CN210959022U

CN210959022U - Composite multilayer substrate

Info

Publication number: CN210959022U
Application number: CN201890000680.9U
Authority: CN
Inventors: 谷口胜己
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2017-05-18
Filing date: 2018-04-17
Publication date: 2020-07-07
Anticipated expiration: 2028-04-17
Also published as: WO2018211897A1

Abstract

The composite multilayer substrate is provided with: a first multilayer substrate (1) having a plurality of first base materials (11-14) stacked; and a second multilayer substrate (2) having a plurality of second base materials stacked on each other, and having a first main surface, a second main surface, and two side surfaces. The second base material is a base material having a lower elastic modulus and a lower relative dielectric constant than the first base material, and the second multilayer board (2) is provided on the first multilayer board (1) in a state in which the first main surface and both side surfaces of the second multilayer board (2) are surrounded by the first base material. A high-frequency circuit is formed on the second multilayer substrate (2).

Description

Composite multilayer substrate

Technical Field

The present invention relates to a composite multilayer substrate in which a plurality of multilayer substrates are combined, and more particularly, to a composite multilayer substrate including a multilayer substrate on which a high-frequency circuit is formed.

Background

As a substrate for electronic devices, for example, a resin multilayer substrate as shown in patent document 1 is used as a substrate which exhibits high density of circuit patterns, easiness of forming circuit patterns inside, flexibility, and the like.

The multilayer substrate shown in patent document 1 is configured by using a thermoplastic resin sheet to which a metal film such as a copper foil is adhered, patterning the metal film of each sheet, laminating them, and pressing them under pressure.

Prior art documents

Patent document

Patent document 1: international publication No. 2014/103530

SUMMERY OF THE UTILITY MODEL

Problem to be solved by utility model

A multilayer substrate formed by laminating a plurality of resin substrates made of a single material as shown in patent document 1 has a problem that if a material is selected with priority given to electrical characteristics such as high-frequency characteristics, mechanical characteristics (mechanical strength) such as rigidity and heat resistance of the resin are insufficient and deformation is likely to occur.

As described above, in a multilayer substrate having low mechanical properties, the mountability when the multilayer substrate is mounted on another substrate is poor. In addition, when electronic components and the like are mounted on the surface of the multilayer substrate, the mountability of the electronic components is poor due to the influence of the irregularities generated on the surface of the multilayer substrate.

Accordingly, an object of the present invention is to provide a composite multilayer substrate in which deterioration of mechanical characteristics is prevented without impairing electrical characteristics of the multilayer substrate.

Means for solving the problems

The composite multilayer substrate of the present invention is constituted as follows.

(1) The utility model discloses a compound multilayer substrate possesses: a first multilayer substrate having a plurality of first base materials stacked; and a second multilayer substrate having a plurality of second base materials stacked, and having a first main surface, a second main surface, and a plurality of side surfaces. The second base material has a lower elastic modulus and a lower relative dielectric constant than the first base material, and the second multilayer board is provided on the first multilayer board in a state where at least two side surfaces and the first main surface of the second multilayer board are surrounded by the first base material. The second substrate forms a high-frequency circuit.

With the above configuration, the second multilayer board is held by the first multilayer board, and therefore the second multilayer board does not require high mechanical properties, and a base material of a material having excellent electrical properties can be used. On the other hand, the first base material as the base material of the first multilayer substrate is not required to have high electrical characteristics, and a base material having excellent mechanical characteristics can be used. Therefore, a composite multilayer substrate excellent in both the electrical characteristics of the high-frequency circuit and the overall mechanical characteristics can be obtained.

(2) Preferably, the main material of the first substrate is a thermosetting resin, and the main material of the second substrate is a thermoplastic resin. With this configuration, a difference in physical properties between the individual second multilayer substrates is less likely to occur as compared with a thermosetting resin accompanied by a large chemical reaction, and variations in electrical characteristics of a high-frequency circuit formed on the second multilayer substrate can be easily suppressed. On the other hand, the first multilayer substrate can be easily configured as a substrate harder and more flat than the second multilayer substrate. Therefore, a composite multilayer substrate having high stability of electrical characteristics and high flatness can be obtained.

(3) The high-frequency circuit is, for example, a high-frequency transmission line. With this configuration, a composite multilayer substrate in which a high-frequency line formed by the second multilayer substrate is arranged on the first multilayer substrate can be easily configured. That is, by forming the high-frequency line on the second multilayer substrate, it is possible to easily configure a composite multilayer substrate including a high-frequency line in which transmission loss occurring in a long path is reduced.

(4) Preferably, the high-frequency transmission line is constituted by a first ground conductor pattern, a second ground conductor pattern, and a signal line pattern located between the first ground conductor pattern and the second ground conductor pattern. Thus, the high-frequency transmission line having a strip line structure can suppress signal leakage and spurious coupling.

(5) A transmission line may be formed on the first multilayer substrate, and the transmission line formed on the first multilayer substrate is preferably a transmission line having a shorter transmission distance than a high-frequency transmission line formed on the second multilayer substrate. This effectively suppresses the transmission loss that increases as the transmission distance increases.

(6) A transmission line may be formed in the first multilayer substrate, and the transmission line formed in the first multilayer substrate is preferably a transmission line having a lower transmission frequency than the high-frequency transmission line formed in the second multilayer substrate. This effectively suppresses the transmission loss that increases with an increase in the transmission frequency.

(7) Preferably, the transmission line formed on the first multilayer substrate is a power supply line. With this configuration, a transmission line can be easily provided without fear of an increase in transmission loss.

(8) The second multilayer substrate may also have a bent portion that is bent or bent in an in-plane direction. This makes it possible to easily construct a composite multilayer substrate including a high-frequency transmission line having a complicated shape. Even if the second multilayer substrate has a bent portion and is easily deformed, the mechanical strength is improved and the electrical characteristics are stabilized by holding the second multilayer substrate on the first multilayer substrate.

(9) The second multilayer substrate may have a bent portion bent or bent in the stacking direction. This makes it possible to easily construct a composite multilayer substrate including a high-frequency transmission line having a complicated shape. Even if the second multilayer substrate has a bent portion and is easily deformed, the mechanical strength is improved and the electrical characteristics are stabilized by holding the second multilayer substrate on the first multilayer substrate.

(10) The second multilayer substrate may be configured to include a plurality of second multilayer substrate portions that intersect with each other in a plan view. This makes it possible to easily construct a composite multilayer substrate including a plurality of high-frequency transmission lines having mutually different transmission directions. Further, since each of the second multilayer substrate portions is held by the first multilayer substrate, the mechanical strength of the whole can be improved, and the electrical characteristics can be stabilized.

(11) The plurality of second multilayer substrate portions may be sandwiched between two of the plurality of first base materials constituting layers adjacent to each other. Thus, a composite multilayer substrate including a plurality of high-frequency transmission lines having transmission directions different from each other can be easily configured without increasing the size in the stacking direction.

(12) The first multilayer substrate may also have mounting electrodes for mounting other components or other substrates. This makes it possible to easily construct a composite multilayer substrate having other components mounted on the surface thereof.

(13) The first multilayer substrate may also have a terminal electrode for surface mounting to another substrate. This makes it possible to construct a composite multilayer substrate that can be surface-mounted on another substrate.

Effect of the utility model

According to the present invention, a composite multilayer substrate in which the mechanical characteristics are prevented from decreasing without impairing the electrical characteristics of the multilayer substrate can be obtained.

Drawings

Fig. 1(a) is a perspective view of a composite multilayer substrate 101 according to the first embodiment. Fig. 1(B) is a perspective view of the mounting member 4 before mounting. Fig. 1(C) is an exploded perspective view showing the structure of a first multilayer substrate 1 and a second multilayer substrate 2 provided inside thereof.

Fig. 2(a) to 2(E) are cross-sectional views showing the structure of the main part of the composite multilayer substrate in the order of the manufacturing steps.

Fig. 3 is a cross-sectional view showing a mounting structure of the composite multilayer substrate to the circuit substrate.

Fig. 4(a) is a cross-sectional view of the second multilayer substrate 2 before lamination of the second base material, and fig. 4(B) is a cross-sectional view of the second multilayer substrate 2.

Fig. 5 is a plan view of the second multilayer board 2 before lamination of the second base material.

Fig. 6(a) to 6(E) are cross-sectional views showing the structure of the main part of the composite multilayer substrate in the order of the manufacturing steps.

Fig. 7 is a cross-sectional view showing a mounting structure of the composite multilayer substrate to the circuit substrate.

Fig. 8(a) is a cross-sectional view of the second multilayer substrate 2 of the second embodiment before lamination of the second base material, and fig. 8(B) is a cross-sectional view of the second multilayer substrate 2.

Fig. 9(a) is a perspective view of the composite multilayer substrate 103 according to the third embodiment. Fig. 9(B) is an exploded perspective view showing the structure of the first multilayer substrate 1 and the second

multilayer substrate sections

2A and 2B provided therein.

Fig. 10 is a perspective view of another second multilayer substrate 2 according to the third embodiment.

Fig. 11 is a plan view of still another second multilayer substrate 2 according to the third embodiment.

Fig. 12(a) and 12(B) are plan views showing the structures of signal lines and electrodes connected to the signal lines in the second multilayer substrate 2 according to the fourth embodiment.

Fig. 13(a) is a plan view of the second multilayer substrate 2 according to the fifth embodiment, and fig. 13(B) is a cross-sectional view of a portion a-a in fig. 13 (a).

Fig. 14 is a plan view of the composite multilayer substrate 106 of the sixth embodiment.

Fig. 15(a) and 15(B) are perspective views showing the arrangement relationship of two second multilayer substrates in the first multilayer substrate according to the seventh embodiment.

Fig. 16 is a cross-sectional view of a composite multilayer substrate 107 according to the seventh embodiment.

Detailed Description

Hereinafter, a plurality of modes for carrying out the present invention will be described with reference to the drawings and by way of specific examples. In the drawings, the same reference numerals are given to the same parts. The embodiments are separately shown for convenience in view of ease of explanation or understanding of the points, but partial replacement or combination of the structures shown in different embodiments can be made. In the second and subsequent embodiments, descriptions of common matters with the first embodiment will be omitted, and only differences will be described. In particular, the same operational effects based on the same structure will not be mentioned in each embodiment.

First embodiment

Fig. 1(a) is a perspective view of a composite multilayer substrate 101 according to the first embodiment. A mounting component 4 is mounted on the upper surface of the composite multilayer substrate 101 (the upper surface of the first multilayer substrate 1). Fig. 1(B) is a perspective view of the mounting component 4 before mounting (mounting). Mounting electrodes E11 and E12 are formed on the upper surface of the first multilayer substrate 1.

Fig. 1(C) is an exploded perspective view showing the structure of the first multilayer substrate 1 and the second multilayer substrate 2 provided therein. The first multilayer board 1 includes

first base materials

11, 12, 13, and 14. The first multilayer substrate 1 incorporates a second multilayer substrate 2.

A cavity CA is formed in the first base material 12, and the second multilayer substrate 2 is accommodated in the cavity CA. The second multilayer board 2 is housed in the cavity CA, and is built into the first multilayer board 1 by heating and pressing the

first base materials

11, 12, 13, and 14 in a stacked state.

The second multilayer substrate 2 has a first main surface MS1, a second main surface MS2, and four side surfaces SS1, SS2, SS3, and SS 4. The second multilayer substrate 2 is incorporated in the first multilayer substrate in a state where the first main surface MS1, the second main surface MS2, and the four side surfaces SS1, SS2, SS3, and SS4 are surrounded by the

first base materials

11, 12, and 13.

As shown in fig. 1(a) and 1(B), the composite multilayer substrate 101 is configured by mounting the mounting component 4 on the mounting electrodes E11 and E12 formed on the upper surface of the first multilayer substrate 1.

Further, the second multilayer board is effective when incorporated in the first multilayer board in a state where at least the first main surface MS1 and both side surfaces SS1 and SS2 are surrounded by the first base material, but mechanical strength can be further improved when four side surfaces are surrounded by the first base material as in the present embodiment.

Fig. 2(a) to 2(E) are cross-sectional views showing the structure of the main part of the composite multilayer substrate in the order of the manufacturing steps. The

first base materials

11, 12, 13, and 14 are thermosetting resin base materials such as prepregs mainly made of glass cloth and epoxy resin, for example. Although not shown in fig. 2(a) to 2(E), an adhesive material layer may be provided between the first base material and the first base material. The mounting electrodes E11, E12, electrodes E13, E14, terminal electrodes T11, and T12 are, for example, electrodes obtained by patterning a metal foil such as a copper foil by photolithography. Further, a plating film of, for example, Ni/Au, Ni/Sn or the like is provided on the surface of these electrodes.

Fig. 2(a) is a cross-sectional view of the

first base materials

11 and 12 before lamination, and fig. 2(B) is a cross-sectional view of the

first base materials

11 and 12 after lamination and temporary pressure bonding. The electrodes E13, E14 connected to the second multilayer substrate 2 are exposed in the cavity CA.

Fig. 2(C) is a cross-sectional view showing a state in which the second multilayer substrate 2 is accommodated in the cavity CA and the second multilayer substrate 2 is electrically connected to the electrodes E13 and E14 via a conductive material such as solder. The second multilayer substrate 2 is mounted on the surface of the first base material 11 in the same manner as in a general surface mounting method to a substrate.

Fig. 2(D) is a diagram showing a state in which the

first base materials

13 and 14 are stacked on the first base material 12. Fig. 2(E) is a cross-sectional view of the

first base materials

11, 12, 13, and 14 after lamination and heat pressing. The second multilayer board 2 is embedded in the cavity CA by the heating and pressing of the first multilayer board 1, and the space provided in the cavity CA is substantially eliminated. The temperature during the heating and pressing is, for example, in the range of 170 ℃ to 270 ℃ (usually 200 ℃ or lower). This temperature is set to be lower than a softening temperature (temperature at which softening starts to a degree at which the shape cannot be held) of the second multilayer substrate 2 described later. This allows the electrical characteristics of the high-frequency circuit formed on the second multilayer substrate 2 to be maintained without substantial deformation of the second multilayer substrate 2.

In this way, the composite multilayer substrate 101 in which the first multilayer substrate 1 and the second multilayer substrate 2 are integrated is configured. Thereafter, the mounting component 4 is mounted on the mounting electrodes E11 and E12 formed on the upper surface of the first multilayer substrate 1 (see fig. 1 a).

Fig. 3 is a cross-sectional view showing a mounting structure of the composite multilayer substrate to the circuit substrate. The circuit board 3 is provided with mounting electrodes E31 and E32, and the terminal electrodes T11 and T12 formed on the lower surface of the first multilayer substrate 1 are connected to the mounting electrodes E31 and E32 via a conductive material such as solder.

The young's modulus of the first multilayer substrate 1 configured as described above is 25GPa, and the relative dielectric constant is about 4.

Next, the structure of the second multilayer substrate 2 is shown. Fig. 4(a) is a cross-sectional view of the second multilayer substrate 2 before lamination of the second base material, and fig. 4(B) is a cross-sectional view of the second multilayer substrate 2. Fig. 5 is a plan view of the second multilayer board 2 before lamination of the second base material.

The second multilayer substrate 2 has

second base materials

20, 21, 22, and 23. The

second substrates

21, 22, and 23 are thermoplastic resin sheets such as polyimide and liquid crystal polymer, and the second substrate 20 is a cover film made of a polyimide film and an adhesive layer.

The signal lines SL are formed on the lower surface of the second base material 22. A ground conductor G1 is formed on the lower surface of the second substrate 21, and a ground conductor G2 is formed on the lower surface of the second substrate 23. Further, input/output electrodes P1 and P2 are formed on the lower surface of the second base material 21. Further, interlayer connection conductors Vs1, Vs2 connected to the end portions of the signal lines SL are formed on the second substrate 21. Further, a plurality of interlayer connection conductors Vg connected to the ground conductors G1, G2 are formed on the

second base materials

21, 22. The second base material 20 is formed with openings H1 and H2 for exposing the input/output electrodes P1 and P2, respectively, and a plurality of other openings for exposing a part of the ground conductor G1. The ground conductor G1 is exposed to a plurality of openings other than the openings H1 and H2 of the second base material 20, and these exposed portions function as mounting auxiliary electrodes.

The ground conductors G1 and G2, the signal line SL, and the input/output electrodes P1 and P2 are obtained by patterning a metal foil of copper or the like by photolithography, for example. The interlayer connection conductors Vs1, Vs2, and Vg are formed by filling via conductor holes formed in the second base material with a metal material containing tin or the like as a main component. Further, the surfaces of the input/output electrodes P1 and P2 are coated with plating films of Ni/Au, Ni/Sn, and the like, for example.

The second multilayer substrate 2 is formed by laminating the

second base materials

20, 21, 22, 23 and performing heat pressing at a temperature exceeding, for example, 240 ℃. The young's modulus of the second multilayer substrate 2 thus configured was 15GPa, and the relative dielectric constant was about 3. Further, an adhesive material layer may be provided between the second base materials.

As shown in fig. 2(a) to 2(E), the input/output electrodes P1 and P2 of the second multilayer substrate 2 are connected to the electrodes E13 and E14 of the first multilayer substrate 1, respectively. Further, a part of the ground conductor G1 of the second multilayer board 2 is connected to a ground electrode formed on the first multilayer board 1.

According to the present embodiment, the following effects are achieved.

(a) Since the second multilayer substrate 2 is held by the first multilayer substrate 1, the second multilayer substrate 2 does not require high mechanical properties, and a base material of a material having excellent electrical properties can be used. On the other hand, the first base material as the base material of the first multilayer substrate 1 is not required to have high electrical characteristics, and a base material having excellent mechanical characteristics can be used. Therefore, a composite multilayer substrate excellent in both the electrical characteristics of the high-frequency circuit and the overall mechanical characteristics can be obtained.

(b) Since the main material of the first substrates 11 to 14 is a thermosetting resin and the main material of the second substrates 20 to 23 is a thermoplastic resin, a difference in physical properties between the individual second multilayer substrates is less likely to occur as compared with a thermosetting resin accompanied by a large chemical reaction, and variations in electrical characteristics of a high-frequency circuit formed on the second multilayer substrate 2 can be easily suppressed. On the other hand, the first multilayer substrate 1 is easily configured as a substrate harder and more flat than the second multilayer substrate 2. Therefore, for example, as shown in fig. 1(a), the mounting member 4 can be easily mounted on the first multilayer substrate 1 having high planarity and high rigidity. Further, since the rigidity of the composite multilayer substrate 101 can be ensured, the composite multilayer substrate 101 has high mountability to other circuit boards and the like.

(c) If the first base material of the first multilayer substrate 1 is a thermosetting resin, a difference in physical properties between the individual first multilayer substrates is likely to occur due to a large chemical reaction, and a variation in characteristic impedance is relatively large. In contrast, since the second base material of the second multilayer board 2 is a thermoplastic resin and is not cured due to a change in physical properties, the thickness dimensional accuracy of each second base material of the second multilayer board 2 is high. Since the second base material of the second multilayer board 2 has a lower relative dielectric constant than the first base material of the first multilayer board 1, when a high-frequency transmission line or the like is provided in the second multilayer board 2, the variation in electrical characteristics with respect to the thickness dimensional accuracy of the base material is small. Therefore, a high-frequency circuit with high electrical characteristics can be formed. In particular, since the characteristic impedance can be accurately set to a predetermined value (for example, unbalanced 50 Ω, balanced 90 Ω, or the like) by the second multilayer substrate 2 alone, the transmission line can be assembled to the composite multilayer substrate while maintaining the electrical characteristics of the transmission line that match the predetermined characteristic impedance.

(d) By using a base material having a lower dielectric loss than the first base material of the first multilayer board 1 for the second base material of the second multilayer board 2, a high-frequency transmission line having a low transmission loss can be formed when a high-frequency transmission line or the like is provided in the second multilayer board 2.

(e) Since the electrodes of the second multilayer substrate are directly connected to the electrodes inside the first multilayer substrate 1 without using a connector, the loss can be reduced and the thickness can be reduced.

(f) Since the above-described mounting auxiliary electrode is present between the input/output electrodes P1, P2 of the second multilayer substrate 2 (halfway along the path), even if the second multilayer substrate 2 is long, a bonding failure of the second multilayer substrate 2 to the first base material 11 can be made less likely to occur.

Second embodiment

The second embodiment shows a composite multilayer substrate including a second multilayer substrate having a connecting portion with a different structure from that of the first embodiment.

Fig. 6(a) to 6(E) are cross-sectional views showing the structure of the main part of the composite multilayer substrate in the order of the manufacturing steps. Fig. 7 is a sectional view showing a mounting structure of the composite multilayer substrate 102 to a circuit substrate. The positions of the electrodes E13 and E14 in the first multilayer substrate 1 and the positions of the input/output electrodes P1 and P2 in the second multilayer substrate 2 are different from those in the first embodiment shown in fig. 2(a) to 2 (E).

Fig. 8(a) is a cross-sectional view of the second multilayer substrate 2 of the present embodiment before lamination of the second base material, and fig. 8(B) is a cross-sectional view of the second multilayer substrate 2.

The signal lines SL are formed on the upper surface of the second substrate 22. A ground conductor G1 is formed on the lower surface of the second substrate 21, and a ground conductor G2 is formed on the upper surface of the second substrate 23. Further, an input/output electrode P1 is formed on the lower surface of the second substrate 21, and an input/output electrode P2 is formed on the upper surface of the second substrate 23. An interlayer connection conductor Vs1 connected to one end of the signal line SL is formed on the second substrate 21, and an interlayer connection conductor Vs2 connected to the other end of the signal line SL is formed on the second substrate 23. Further, a plurality of interlayer connection conductors Vg connected to the ground conductors G1, G2 are formed on the

second base materials

21, 22, 23. The second base material 20 is formed with an opening for exposing the input/output electrode P1 and a plurality of openings for exposing a part of the ground conductor G1. Similarly, the second base material 24 is formed with an opening for exposing the input/output electrode P2 and a plurality of openings for exposing a part of the ground conductor G2.

The second multilayer board 2 is formed by laminating the

second base materials

20, 21, 22, 23, and 24 and heating and pressing the laminated layers.

Unlike the second multilayer substrate 2 shown in fig. 4(a) and 4(B), the second multilayer substrate 2 according to the present embodiment includes the input/output electrode P1 on the first main surface MS1 side and the input/output electrode P2 on the second main surface MS2 side.

As shown in fig. 6(a) to 6(E), the input/output electrodes P1 and P2 of the second multilayer substrate 2 are connected to the electrodes E13 and E14 of the first multilayer substrate 1, respectively. The ground conductors G1 and G2 of the second multilayer board 2 are connected to the ground electrode formed on the first multilayer board 1.

Third embodiment

In the third embodiment, an example of a composite multilayer substrate in which the shape of the second multilayer substrate is different from that of the first embodiment and the second embodiment is shown. Fig. 9(a) is a perspective view of the composite multilayer substrate 103 according to the third embodiment. Mounting

components

4A and 4B are mounted on the upper surface of the composite multilayer substrate 103 (the upper surface of the first multilayer substrate 1). Fig. 9(B) is an exploded perspective view showing the structure of the first multilayer substrate 1 and the second

multilayer substrate sections

2A and 2B provided therein. The first multilayer board 1 includes

first base materials

11, 12, 13, and 14. The first multilayer substrate 1 incorporates second

multilayer substrate portions

2A and 2B.

The first base material 12 is formed with cavities CA1 and CA2, and the second

multilayer substrate sections

2A and 2B are accommodated in the cavities CA1 and CA 2. The second

multilayer substrate portions

2A and 2B are accommodated in the cavities CA1 and CA2, and are built in the first multilayer substrate 1 by being heated and pressed in a state where the

first base materials

11, 12, 13, and 14 are stacked.

Mounting electrodes E11, E12, E15, and E16 are formed on the upper surface of the first base material 14. As shown in fig. 9(a), the mounting

components

4A and 4B are mounted on the mounting electrodes E11, E12, E15, and E16.

The second multilayer substrate portion 2A shown in fig. 9(B) is crank-shaped. As described above, the second multilayer substrate is not limited to a rectangular parallelepiped shape, and may have a bent portion that is bent or bent in the in-plane direction. This makes it possible to easily construct a composite multilayer substrate including a high-frequency transmission line having a complicated shape. As shown in fig. 9(B), a plurality of second multilayer substrates may be incorporated in the first multilayer substrate 1.

Fig. 10 is a perspective view of another second multilayer substrate 2 according to the third embodiment. The second multilayer substrate 2 has a C-shape or コ -shape in a plan view. In the second multilayer substrate 2, a strip line is formed by a signal line and a ground conductor which is positioned so as to sandwich the signal line from top to bottom. The second multilayer substrate 2 is provided with at least two first connection portions CP1 and second connection portions CP 2. Input/output electrodes are formed at the connection portions CP1 and CP2, respectively. Electrodes connected to the input/output electrodes are formed on the first multilayer substrate having the second multilayer substrate 2 built therein.

Fig. 11 is a plan view of still another second multilayer substrate 2 according to the third embodiment. The second multilayer substrate 2 is annular or quadrangular. In the second multilayer substrate 2, a strip line is formed by the signal line SL and a ground conductor that is positioned so as to sandwich the signal line SL from top to bottom. In this manner, the second multilayer substrate may have a closed ring shape.

As described above, if the high-frequency transmission line has a stripline structure, leakage and unnecessary coupling of signals can be suppressed.

Fourth embodiment

In the fourth embodiment, an example of a composite multilayer substrate including a second multilayer substrate having three or more input/output units is shown.

Fig. 12(a) and 12(B) are plan views showing the structures of signal lines and electrodes connected to the signal lines in the second multilayer substrate 2. Here, illustration of the ground electrode is omitted.

In the example shown in fig. 12(a), the electrodes P11 and P12 are formed at the first connection portions CP11 and CP12, and the electrode P2 is formed at the second connection portion CP 2. Signal lines SL11 and SL12 are formed between the electrode P11 and the electrode P12, and a signal line SL2 is formed between the connection point of the signal lines SL11 and SL12 and the electrode P2. In this way, it is also possible to constitute a composite multilayer substrate using a second multilayer substrate having three connection portions and a line branched.

In the example shown in fig. 12(B), the electrodes P11 and P12 are formed at the first connection portions CP11 and CP12, and the electrodes P21 and P22 are formed at the second connection portion CP 2. A signal line SL1 is formed between the electrode P11 and the electrode P21, and a signal line SL2 is formed between the electrode P12 and the electrode P22. In this way, it is also possible to constitute a composite multilayer substrate using a second multilayer substrate having three connection portions and constituting two lines.

In the branching type shown in fig. 12(a), a frequency filter may be provided to constitute a splitter such as a duplexer or a diplexer.

In addition, a second multilayer substrate having four or more connection portions can be similarly provided.

Fifth embodiment

In the fifth embodiment, an example of a composite multilayer substrate including a second multilayer substrate having a transmission line configuration different from the embodiments described so far is shown.

Fig. 13(a) is a plan view of the second multilayer substrate 2 according to the present embodiment, and fig. 13(B) is a cross-sectional view of a portion a-a in fig. 13 (a).

The second multilayer substrate 2 of the present embodiment is a laminate of a plurality of second base materials on which various conductor patterns are formed. In this example, three signal lines SL1, SL2, and SL3 and ground conductors G formed on both sides and above and below thereof constitute three ground coplanar lines extending in the Y-axis direction. Further, the signal line interlayer connection conductor Vs1 and the ground line interlayer connection conductor Vg extending in the stacking direction constitute a coaxial line extending in the Z-axis direction.

As shown in this embodiment, the second multilayer substrate 2 may be provided with signal lines that pass through different height positions in the stacking direction. Further, a signal line extending in the stacking direction may be formed.

Sixth embodiment

In the sixth embodiment, an example of a composite multilayer substrate including a first multilayer substrate having a high-frequency transmission line, a low-frequency line, and a power supply line is shown.

Fig. 14 is a plan view of the composite multilayer substrate 106 of the present embodiment. The first multilayer substrate 1 incorporates second multilayer substrates 2H1 and 2H 2. A plurality of mounting

components

4A, 4B, 4C, etc. are mounted on the first multilayer substrate 1. Further, a plurality of connectors are formed on one side of the first multilayer substrate 1.

The composite multilayer substrate 106 is a motherboard of a server installed in a data center or the like, for example. For example, the mounting component 4A is a CPU, the mounting component 4B is a signal control component, and the mounting component 4C is a power supply circuit component. The first multilayer substrate 1 is provided with a low-frequency transmission line S2 for connecting the mounted component 4A and the mounted component 4B. Further, the first multilayer substrate 1 is provided with high-frequency transmission lines S11, S12, S13, and S14 for connecting the mounted component 4A and the connector. Further, the first multilayer board 1 is provided with a power supply line S3 for connecting the mounted component 4C and the mounted component 4A and the like.

The low-frequency transmission line S2 is a microstrip line formed on the surface or the surface layer of the first multilayer substrate 1. The high-frequency transmission lines S11, S12, S13, and S14 are differential strip lines (balanced strip lines) formed inside the first multilayer substrate 1.

Differential strip lines (balanced strip lines) are formed on the second multilayer substrates 2H1 and 2H2, respectively. That is, the second multilayer substrates 2H1, 2H2 function as differential strip lines, respectively.

In this example, high-frequency transmission lines formed on the second multilayer substrates 2H1 and 2H2 are used as transmission lines having a longer transmission distance than the high-frequency transmission lines S11, S12, S13 and S14 formed on the first multilayer substrate 1. High-frequency transmission lines formed on the second multilayer substrates 2H1 and 2H2 are used as transmission lines having a higher transmission frequency (higher data transmission speed) than the high-frequency transmission lines S11, S12, S13 and S14 formed on the first multilayer substrate 1. For example, a 10Gbps transmission line is formed by a microstrip line, and a higher speed transmission line such as 100Gbps or 200Gbps is formed by a strip line. Thus, leakage noise from the high-speed transmission line can be suppressed.

Generally, as the transmission distance in a transmission line is longer or the transmission frequency is higher, the attenuation of a signal becomes larger, and if the attenuation is increased to a predetermined value or more, a signal repeater (driver)/repeater (repeater) IC is necessary in order to maintain a predetermined noise margin. However, in the present embodiment, since the attenuation amount in the high-frequency transmission line constituting the second multilayer substrate is small, the application to a transmission path having a long transmission distance and a high transmission frequency makes it unnecessary to use a signal repeater/repeater IC.

As described above, the high-frequency transmission line formed on the second multilayer substrate is preferably used as a transmission line having a relatively long transmission distance or a transmission line having a relatively high transmission frequency. This effectively suppresses transmission loss.

Seventh embodiment

In the seventh embodiment, a few examples of the arrangement structure of the second multilayer substrate with respect to the first multilayer substrate are shown.

Fig. 15(a) and 15(B) are perspective views showing the arrangement relationship of two second multilayer substrates in the first multilayer substrate. The first multilayer substrate is not shown. In both of the examples of fig. 15(a) and 15(B), a second multilayer substrate portion 2X extending in the X-axis direction and a second multilayer substrate portion 2Y extending in the Y-axis direction are provided. In this manner, the plurality of second multilayer substrate portions may cross each other in a plan view. This makes it possible to easily construct a composite multilayer substrate including a plurality of high-frequency transmission lines having mutually different transmission directions without providing an interlayer connection conductor such as a via hole in the first multilayer substrate 1.

In particular, in the example of fig. 15(a), the second multilayer substrate section 2X and the second multilayer substrate section 2Y are sandwiched between two of the plurality of first base materials constituting layers adjacent to each other. Therefore, the second multilayer substrate part 2X and the second multilayer substrate part 2Y are located at the same height in the first multilayer substrate. According to this structure, a composite multilayer substrate including a plurality of high-frequency transmission lines having transmission directions different from each other can be easily configured without increasing the size in the stacking direction.

On the other hand, in fig. 15(B), if the first base material is interposed between the second multilayer substrate portion 2X and the second multilayer substrate portion 2Y, the deformation of the portion where the second multilayer substrate portion 2X and the second multilayer substrate portion 2Y overlap can be suppressed, the mechanical strength can be improved, and the electrical characteristics can be stabilized.

Fig. 16 is a cross-sectional view of the composite multilayer substrate 107. A mounting component 4 is mounted on the upper surface of the first multilayer substrate 1. A second multilayer substrate 2 is provided on a surface layer of the first multilayer substrate 1 on the upper surface side. The second multilayer substrate 2 forms a differential strip line. The second multilayer board 2 is provided on the first multilayer board 1 in a state where the first main surface MS1 and the side surfaces SS1 and SS2 are surrounded by the base material of the first multilayer board. The second main surface MS2 of the second multilayer substrate 2 is exposed.

In this way, the second multilayer substrate 2 can be integrated without being completely embedded in the first multilayer substrate 1, and a predetermined mechanical strength of the second multilayer substrate 2 can be maintained. Further, since the plurality of second multilayer substrates have the bent portions bent or bent in the stacking direction, the composite multilayer substrate including the high-frequency transmission line having a complicated shape can be easily configured.

The intersection angle between the plurality of second multilayer substrates is not limited to 90 degrees, and may be any of 30 degrees, 45 degrees, 60 degrees, and the like. In particular, if the transmission lines formed on the second multilayer substrates are strip lines, wasteful coupling between the transmission lines can be suppressed.

Other embodiments

Although the examples shown in fig. 2(a) to 2(E) and 16 show an example in which a cavity is formed in advance in the first multilayer substrate 1 and the second multilayer substrate 2 is embedded in the cavity, the cavity is not necessary when the fluidity of the first base material of the first multilayer substrate 1 is high. For example, a composite multilayer substrate in which the second multilayer substrate 2 is embedded in the first multilayer substrate 1 may be configured by sandwiching and heating and pressing a plurality of first base materials together with the second multilayer substrate when laminating them.

Finally, the above description of the embodiments is in all respects illustrative and not restrictive. It is obvious to those skilled in the art that the modifications and variations can be appropriately made. The scope of the present invention is shown not by the above-described embodiments but by the claims. Further, the scope of the present invention includes modifications from the embodiments within the scope equivalent to the claims.

Description of the reference numerals

CA. CA1, CA 2: a cavity;

CP1, CP11, CP 12: a first connection portion;

CP 2: a second connecting portion;

e11, E12, E15, E16: mounting an electrode;

e13, E14: an electrode;

e31, E32: mounting an electrode;

G. g1, G2: a ground conductor;

h1, H2: an opening;

MS 1: a first major face;

MS 2: a second major face;

p1, P2: an input/output electrode;

p11, P12: an electrode;

p21, P22: an electrode;

s11, S12, S13, S14: a high-frequency transmission line;

s2: a low frequency transmission line;

s3: a power line;

SL, SL1, SL2, SL 3: a signal line;

SL11, SL 12: a signal line;

SS1, SS2, SS3, SS 4: a side surface;

t11, T12: a terminal electrode;

vg: an interlayer connection conductor for grounding;

vs1, Vs 2: a signal line interlayer connection conductor;

1: a first multilayer substrate;

2. 2H1, 2H 2: a second multilayer substrate;

2A, 2B: a second multilayer substrate portion;

2X, 2Y: a second multilayer substrate portion;

3: a circuit substrate;

4. 4A, 4B, 4C: a mounting member;

11. 12, 13, 14: a first substrate;

20. 21, 22, 23, 24: a second substrate;

101. 102, 103, 106, 107: and (3) compounding the multilayer substrate.

Claims

1. A composite multi-layer substrate is characterized in that,

the disclosed device is provided with: a first multilayer substrate having a plurality of first base materials stacked; and a second multilayer substrate having a plurality of second base materials stacked on each other and having a first main surface, a second main surface, and a plurality of side surfaces,

the second substrate is a substrate having a low elastic modulus and a low relative dielectric constant as compared with the first substrate,

the second multilayer board is provided on the first multilayer board in a state where at least two side surfaces of the plurality of side surfaces and the first main surface of the second multilayer board are surrounded by the first base material,

a high-frequency circuit is formed on the second multilayer substrate.

2. The composite multilayer substrate of claim 1,

the main material of the first substrate is a thermosetting resin, and the main material of the second substrate is a thermoplastic resin.

3. The composite multilayer substrate of claim 1 or 2,

the high-frequency circuit is a high-frequency transmission line.

4. The composite multilayer substrate of claim 3,

the high-frequency transmission line is composed of a first ground conductor pattern, a second ground conductor pattern, and a signal line pattern between the first ground conductor pattern and the second ground conductor pattern.

5. The composite multilayer substrate of claim 3,

a transmission line having a shorter transmission distance is formed in the first multilayer substrate than the high-frequency transmission line formed in the second multilayer substrate.

6. The composite multilayer substrate of claim 3,

a transmission line having a lower transmission frequency than the high-frequency transmission line formed on the second multilayer substrate is formed on the first multilayer substrate.

7. The composite multilayer substrate of claim 6,

the transmission line formed on the first multilayer substrate is a power supply line.

8. The composite multilayer substrate of claim 1 or 2,

the second multilayer substrate has a bent portion that is bent or bent in an in-plane direction.

9. The composite multilayer substrate of claim 1 or 2,

the second multilayer substrate has a bent portion bent or inflected in the stacking direction.

10. The composite multilayer substrate of claim 1 or 2,

the second multilayer substrate is configured from a plurality of second multilayer substrate portions that intersect with each other in a plan view.

11. The composite multilayer substrate of claim 10,

the plurality of second multilayer substrate sections are sandwiched between two of the plurality of first base materials that constitute layers adjacent to each other.

12. The composite multilayer substrate of claim 1 or 2,

the first multilayer substrate has mounting electrodes for mounting other components or other substrates.

13. The composite multilayer substrate of claim 1 or 2,

the first multilayer substrate has a terminal electrode for surface mounting to another substrate.